FZUS61 KBUF 042003 GLFSL Forecast for the Saint Lawrence River including the Thousand Islands Region National Weather Service Buffalo NY 403 PM EDT Tue Aug 4 2026 SLZ022-024-050300- Saint Lawrence River from Cape Vincent to Saint Regis 403 PM EDT Tue Aug 4 2026 .TONIGHT...Southwest winds 10 knots or less becoming south. Mainly clear. .WEDNESDAY...South winds 10 knots or less becoming southwest. Sunny. .WEDNESDAY NIGHT...Southwest winds less than 10 knots. A chance of showers overnight. .THURSDAY...South winds 10 knots or less becoming southwest. A chance of showers in the morning, then a chance of showers and thunderstorms in the afternoon. .THURSDAY NIGHT...Southwest winds less than 10 knots. A chance of showers and thunderstorms in the evening. .FRIDAY...Light and variable winds. A chance of showers and thunderstorms during the day, then showers likely with a chance of thunderstorms Friday night. .SATURDAY...Southwest winds 10 knots or less. Showers likely with a chance of thunderstorms during the day, then a chance of showers and thunderstorms Saturday night. .SUNDAY...Southwest winds 5 to 10 knots. A chance of showers. Winds and waves higher in and near thunderstorms. $$